Detailed Steps for Tuning In-Flight Beams

From ATLAS Accelerator In-Flight Beam Program
Jump to navigation Jump to search

Overview of the steps for In-flight beam delivery

Once steps for degraded beam tuning have been completed and a good focus is found at the RAISOR midplane (Separate detailed sheet for this), the steps below can be used to help guide the identification and tuning of the secondary beam.

  1. Acquire information on primary/degraded beam tunes and prep for beam
    1. Get docs from operations on primary and degraded beam TOFs and the charge state and slit scan data
    2. Acquire the final cup/collimator FC currents and any notes on degraded beam transmission
    3. Insert detector of choice, make sure HV and preamps are on and daq is alive w/ noise etc
  2. Get a reference spectrum from the degraded beam (can be done at RAISOR exit or target depending)
    1. Cut back beam by x100 w/ slits (not RAISOR slits) first then insert all available attenuation (~x15 Million)
    2. Place beam on detectors and slowly remove attenuation until rates are roughly >100 Hz & <1000 Hz
    3. Take ref spectrum - optimize daq params and save the settings file as they should not be changed for the duration of the run
  3. Determine the RF Sweeper phase for full or largest degraded beam removal
    1. Set degraded beam rate to few hundred Hz and get Grafana running
    2. Have operations turn on Sweeper to Voltage=2 and phase=0 to start
    3. Note: You already may see a reduction in the beam rate do not increase beam current to get back to few hundred Hz
    4. Scan the RF Sweeper Phase in 5 degree steps, noting on Grafana or elsewhere, what angle the beam rate is a minimum
    5. Do smaller steps of ~1 degreed around the regions of the minimum to try and get the best angle
    6. TURN OFF THE SWEEPER FOR NOW (or maybe only needs to have V=0)
    7. Should be back to the few hundred Hz rate as at the beginning
  4. Identify the secondary beam Note: if secondary beam is weak or scale factor is unreliable see optional step below.
    1. Scale all RAISOR magnets to the desired rigidity of the secondary beam (calculation of this value from TOF data etc is done on the inflXXX pages accessible from the wiki home).
    2. Remove attenuation as necessary to achieve the 100 - 1000 Hz rates on the Si detectors
    3. Take a fixed time run with the daq (Compass and Ryan's boxscore separately would be good to cross check things).
    4. Identify the isotope of interest based on calculated energies or previous production of the isotope
    5. Calculate the rate of the isotope of interest as the pps / pnA [note: pnA value from FCA001 divided by q of primary beam]
    6. Identify the same isotope on the data room scope (either from DE or E signal), and try to confirm the rate as pps / pnA
    7. Repeat rate measurement for RAISOR scaling factors both +1% and -1% around the initial value to ensure you are on the peak of the yield (i.e. if scale was 3% from degraded, then try 2% and 4%)
    8. Optional: If secondary beam not found in Option 1, or is know to be difficult
      1. Incrementally scale the RAISOR magnets in 1% steps, each time removing attenuation to achieve the 100-1000 Hz rates and searching for the beam of interest
  5. Optimize and transmit secondary beam
    1. Once beam is on peak scale factor, make sure operators have access to direct rate of secondary beam either via analog or software (boxscore)
    2. Operators should optimize tune at the RAISOR exit
    3. After operators scale the secondary beam line elements for transport to the target, check spectra at the target to ensure ID of the correct beam
    4. If needed, follow the steps to get reference spectra for the target detectors as well by going back to the degraded beam settings (dont forget all the attenuation)
    5. Once isotope has been identified at the target, take a measure of the pps / pnA rate
    6. Operators should now optimize tune at the target position
    7. Optional: Turning on the RF Sweeper:
      1. TBD


  • primary beam - the beam species and charge state taken out of the source at the ATLAS energy requested
  • degraded beam - the same beam species as the primary beam but at a different (lower) energy and most likely different (higher) charge state
  • production target - the target put in place before RAISOR, e.g., Be foil or Gas Cell